The drying apparatus for powdered or granular material according to the prior art is shown in FIG. 6a and FIG. 6b. According to the drying hopper 101 shown in the figure, a tubular heat conducting wall 102 made of a material with high heat conductivity like aluminum is provided at the periphery, an external heating means 103 comprised of a band heater is provided outside of the wall 102, a heat conducting tube 104 made of a material with high heat conductivity like aluminum is provided in the drying hopper 101, and a central heating means 105 comprised of a pipe heater is included at the center.
Plural compartment walls 106 with same thickness are vertically projected out of the heat conducting wall 102 with an even space in a radial manner into the center and plural compartment walls 107 with same thickness are vertically projected out of the heat conducting tube 104 at the center with an even space in a radial manner into the heat conducting wall 102. There are some spaces between the tip ends of opposing these compartment walls 106, 107 50 as not to prevent the powdered or granular material from flowing (see Japanese Utility Model No.30578778).
However, small amount and many kinds of resin goods have been produced recently, further the goods have become small. Therefore, the resin molding machine is required to be compact, so that a more compact and simply constructed drying apparatus has been desired in order to meet such demand.